Conventional seating devices typically have some variant of a vertical planar backrest with a surface applying support pressure to large contact planes on a seat occupant's thoracic and cervical back regions to assist in maintaining an upright sitting position. These backrest surfaces are typically flat or slightly molded to conform to the shape of a seat occupant's entire back. Most seat occupants tend to bend their spine in a convenient but unhealthy convex protruding manner against the conventional backrest.
To enhance comfort, improve posture, and induce healthy seating habits, seating device backrests exist with slightly convex contact planes, or separate embedded protruding structural elements, or attachments, supporting sustained pressure on a seat occupant's (a) “spinal” lumbar/thoracic region along the vertical center of the back, and (b) “muscular” lumbar/thoracic region radiating outward from the “spinal” region to the extremities of the back and housing the primary back muscles. Typical prior art lumbar supportive backrests with lumbar supports comprise a cushioned attachment or embedded backrest element, or otherwise form an extremity pressure element anchored to a framework within or connected to the seating device's larger traditional vertical planar backrest. These devices restrict horizontal flexibility and lateral maneuverability of a seat occupant by contacting and restricting movement of large planar sections of a seat occupant's back.
Further, these prior art devices apply wide planes of horizontal pressure necessitated by the requirement they conform to, or comprise part of, the broader seating device backrest elements, or because they are designed following a premise that the best mechanism to support a seat occupant's body is to apply pressure to both the skeletal middle and muscular extremities of the lumbar/thoracic back regions. But, this pressure to the muscles in the lumbar and upper thoracic back regions, and the resultant reduction of back muscle blood flow, are the most common sources of chronic pain, discomfort and long term back injury for people who often sit in seating devices for long periods of time on a daily basis.
While designed to encourage a seat occupant to adopt a healthy seating posture, prior art lumbar supports, and the seat backrests including them, are limited in the flexibility and maneuverability they offer a seat occupant because their intended contact points apply broad planar pressure across most or all of a seat occupant's proximal thoracic and lumbar regions' muscle, ligament and tendon tissues protruding and radiating out from the spinal center of the back to the back's horizontal extremities. Because these prior art lumbar supports apply a generalized rectangular pressure to large planar sections of a seat occupant's entire spinal and muscular lumbar and thoracic hack regions, (a) they reduce needed muscular blood-flow and oxygenation and cause pressure contact injury to the lumbar muscles, ligaments and tendons, and (b) they offer the seat occupant the comfortable option to slouch against, or avoid, the lumbar supports and bypass the beneficial posture improving elements of the supports.
Accordingly, a seating device and backrest is needed that obviates the problems associated with past devices.